Fig. 387.—Armature coil taping machine. Numerous machines have been invented for taping armature coils. They consist essentially of a device which revolves a roll of tape around the coil, in such a direction that the tape is unwound from the roll and rewound on the coil. The speed at which the coil is fed through the machine will determine the overlapping of the tape.
Ques. What other kinds of retainer are used on smooth core armatures?
Ans. They require several binding ribbons or brass bands placed around the winding to prevent the inductors being thrown off the core by centrifugal force.
Ques. With slotted armatures what provision must be made for retaining the inductors in position?
Ans. Retaining wedges must be inserted into the notches or between the projecting tops of the teeth.
Fig. 388.—Front view of large armature for direct connected dynamo, built by the General Electric Co.
Ques. How are the wedges made?
Ans. They are usually made of well baked hard wood, such as hornbeam, or hard white vulcanized fibre. Sometimes a springy strip of German silver is used.